Apparatus, Method and Computer Program for Emergency Call

1. A user equipment, comprising: at least one processor; and at least one memory including computer program code; wherein the computer program code is configured to, when executed by the at least one processor, cause the user equipment at least to perform: when the user equipment operates in a dual registration mode: upon receiving a call request and determining that the call request is an emergency call request, determining whether the user equipment is camping in a cell of a first radio access technology, wherein the cell of the first radio access technology is connected to a core network; upon determining that the user equipment is camping in the cell of the first radio access technology, determining whether an emergency service is supported only in cells of a second radio access technology, wherein the second radio access technology is different than the first radio access technology and the cells of the second radio access technology are connected to the core network; upon determining that the emergency service is supported only in the cells of the second radio access technology, determining whether the user equipment supports access to emergency services fallback; upon determining that the user equipment does not support emergency services fallback, determining whether the user equipment supports access to the core network via the cells of the second radio access technology, upon determining that the user equipment supports access to the core network via the cells of the second radio access technology, attempting to select a cell of the cells of the second radio access technology; and upon selecting the cell of the cells of the second radio access technology, performing the emergency call by triggering establishment of a packet data unit session for the emergency service via the cell of the second radio access technology that is selected.

2. The user equipment according to claim 1, wherein the computer program code is configured to, when executed by the at least one processor, further cause the user equipment at least to perform: disabling first radio access technology capability of the user equipment.

3. The user equipment according to claim 1, wherein the first radio access technology comprises third generation partnership project new radio.

4. The user equipment according to claim 1, wherein the core network comprises a fifth generation core network.

5. The user equipment according to claim 1, wherein the second radio access technology comprises an evolved universal mobile telecommunication system terrestrial radio access network.

6. A method for a user equipment, the method comprising, when the user equipment operates in a dual registration mode: upon receiving a call request and determining that the call request is an emergency call request, determining whether the user equipment is camping in a cell of a first radio access technology, wherein the cell of first radio access technology is connected to a core network, wherein the cell is a cell of first radio access technology; upon determining that the user equipment is camping in the cell of the first radio access technology, determining whether an emergency service is supported only in cells of the second radio access technology, wherein the second radio access technology is different than the first radio access technology and the cells of the second radio access technology are connected to the core network; upon determining that the emergency service is supported only in the cells of the second radio access technology, determining whether the user equipment supports access to emergency services fallback; upon determining that the user equipment does not support emergency services fallback, determining whether the user equipment supports access to the core network via the cells of the second radio access technology, and upon determining that the user equipment supports access to the core network via the cells of the second radio access technology, attempting to select a cell of the cells of the second radio access technology; and upon selecting the cell of the cells of the second radio access technology, performing the emergency call by triggering establishment of a packet data unit session establishment for the emergency service via the cell of second radio access technology that is selected.

7. A non-transitory computer-readable medium comprising instructions which, when executed by one or more processors of a user equipment, cause the one or more processors of the user equipment, to perform, when the user equipment is operating in a dual registration mode: upon receiving a call request and determining that the call request is an emergency call request, determining whether the user equipment is camping in a cell of a first radio access technology, wherein the cell of the first radio access technology is connected to a core network; upon determining that the user equipment is camping in the cell of the first radio access technology, determining whether an emergency service is supported only in cells of a second radio access technology, wherein the second radio access technology is different than the first radio access technology and the cells of the second radio access technology are connected to the core network; upon determining that the emergency service is supported in only the cells of the second radio access technology, determining whether the user equipment supports emergency services callback; upon determining that the user equipment does not support emergency services fallback, determining whether the user equipment supports access to the core network via the cells of the second radio access technology, and upon determining that the user equipment supports access to the core network via the cells of the second radio access technology, attempting to select a cell of the cells of the second radio access technology; and upon selecting the cell of the cells of the second radio access technology, performing the emergency call by triggering establishment of a packet data unit session for the emergency service via the cell of the second radio access technology that is selected.